Actually, for the types of applications they're talking about, I think I'd prefer a hydraulic elevator. I'm guessing that there must be some sort of advantage to this vacuum system or else there'd be no market for it (although, there's little evidence that there actually is a market for it). Maybe there is some value to this system. Perhaps it's cheaper. Perhaps it's better in some way that I haven't yet discerned. Or, perhaps the investors in this company are just idiots. Whatever. I don't personally see the allure. And I 100% agree with the statements about being able to store overpressure in a tank. You can store vacuum in a tank, but the highest pressure differential you can possibly get is 15psi. So you'd need a really significantly larger tank to store the vacuum in.
It would seem to me that there's a limit to the amount of vacuum you can get above an elevator, but no limit in the pressure you could generate below it. I mean, if the elevator is 4 feet across, then the absolute theoretical limit of wieght that could be pulled up by suction (assuming standard sea-level pressure) would be...
interesting. Google can't parse:
(pi * ((inches in 1 foot * 2)^2) * psi in 1 atm) / lbs in 1 ton
OK. I guess that's not so very strange after all. In a 4 foot wide elevator, you can lift 13 tons with a hard vacuum above it. Damn. 15psi sure does add up quick.
If, theoretically, I personally were to get infected with some sort of phishing keystroke logger, what would an attacker get? well, besides this post, they would get... some oddness. I click on my mozilla icon, I click on my bookmark for my online banking, I click on the link to passwordsafe, I enter the password for my local password database (which, of course, is an extremely sensitive password, but isn't of much use to someone who doesn't have the database file itself.) I double-click the entry for my online banking info, and hit "ctrl-v".
Of course, if an attacker could install a keystroke logger, he could also steal my passwordsafe database. Or he could copy off the contents of my clipboard at the appropriate time. Or he could corrupt my browser and pervert it such that, for instance, it would send the data in any https-based POST's to him as well. But all of those further fragment his attack strategy. What about people who use password managers other than passwordsafe? How about people who use different browsers? Will he write his software to pervert IE, Mozilla, Firefox, Opera, lynx? It does make his challenge a bit tougher... Which is always a good thing.
If someone is considering pirating proprietary software, I will suggest they try an open-source alternative first because, well, I actually *do* care about software piracy.
Second, I will suggest things like firefox and thunderbird to people, because if my suggestion means that one random user *might* install said software, that user will have a *slightly* better chance of not becoming part of some evil hacker's vast zombie network, and that makes *my* network more secure. It's a very slight gain, which is why I don't put a lot of effort into it, but a successful suggestion to a random user *will* perk up my day for this reason. Kinda like finding a penny on the street.
The only ones that mean anything are.edu,.gov, and.XX for country codes
I would submit that.mil and.arpa also have meaning. Actually, very important meaning. The moral of the story is: The harder it is to get a domain name in a TLD, the more valuable that TLD is to the end user. The easier it is to get a domain in a particular TLD, the more valuable that TLD is percieved to be by its registrars.
OK, there are some interesting things here... First, there are limitations. Off the top of my head, those limitations are:
The fingerprinted machine must be communicating using TCP (or another protocol with timestamps, but there aren't many I can think of other than TCP)
It must implement RFC 1323 TCP timestamps. For instance, a quick `echo 0 >/proc/sys/net/ipv4/tcp_timestamps` should keep you from being fingerprinted using this technique.
It must implement timestamps as specified. Filling that option with random numbers, or with timestamps skewed by random amounts, or with timestamps skewed by N number of predetermined time functions (i.e., an offset and a drift, making it appear that you are N different machines) would make it more difficult to do this fingerprinting.
That said, there are some usefull things you could do with this. One example I can think of would be to detect some obfuscated scanning techniques. As an example, nmap impliments idle scanning, which is usually reasonably obvious because of the characteristic SYN->SYN/ACK->RST sequence, especially if the SYN and RST have different TTL's. Adding timestamp checks would make it more obvious (although, just as difficult to track down the original scanner).
Also, if someone used a decoy scan in nmap, it might be reasonably easy to tell which source addresses were really the same machine. You would probably also get enough information to construct a fairly accurate timestamp/skew profile of that machine. If you ever saw those IP addresses again, then you'd be able to check whether it was the real machine.
But, these are just my own ramblings. At the very least it seems to be interesting work (although the article linked is pretty crummy)
Pointless for anti-theft, but looks like it could be usefull for social engineering. Showing up at someone's office building with a laptop and saying "hey, can I plug into your internal network for a few minutes?" isn't likely to have too much success. Your chances are much better if you show up with 1) a tool belt and CWA polo shirt, 2) a pizza box, or 3) a cleaning cart and a complete inability to speak english.
Of course, the real hilarity ensues when you bring your pizza box with a laptop in it with you to the airport...
But it's such an idiotic statement to begin with. Of course tabbed browsing isn't important to IE users. If it were important to someone, they would cease to be an IE user. It would be a similar statement to say that "Features such as high gas mileage are not important to Hummer users." While the statement is true, it has no bearing on whether or not high gas mileage is important to users of cars. Similarly, tabbed brwosing is important to many browser users, but not all. Probably, most of the browser users out there for whom it is important are using Firefox, Mozilla, Opera, etc., while some of the users for whom it is not important may be using IE (unless there is some other feature that IE lacks and other browsers have).
"Virginia is considering just such a measure, largely because several of the 9/11 hijackers were licensed there."
because wouldn't everyone agree that it would have been just so much better if the 9/11 hijackers had Virginia drivers licenses with RFID chips embedded in them when they flew into the WTC. Sigh. Putting RFID chips in drivers licenses doesn't make it any harder for someone (terrorist or not) to get a drivers license. It wouild make just about as much sense to say "Virginia is considering just such a measure because tasty smoked ham is made in Virginia. There's no correlation between the two, but every effect must have a cause, so we'll use ham." I'm thinking that the "logic" here is that if they know someone is a terrorist, they can use RFID chip scanners to find them more easily. But if you know someone's a terrorist, then maybe you should arrest them when they come to pick up their driver's license in the first place, or when they get their airline ticket, or when they get pulled over by a cop for speeding, or at any other time when they actually present their driver's license and/or name. This is a solution to a problem we'd love to have. If someone could solve the problem of figuring out who's a terrorist, and the only obstacle was in finding them, then maybe this would be usefull. As it is, this is a solution to a problem that doesn't exist.
There is the "worst movie that I was looking forward to", i.e. one that I thought I might enjoy, but was horribly, horribly disappointed at. That would have to be Highlander 2.
And then there's just plain bad. I'm thinking that would be The Cars that Ate Paris. (and no, it's not a porno about a 70's Boston rock band's sexual escapades with a vapid blonde heiress. That might have at least been funny.)
Well, you could always go to the other extreme. Install a stick of dynamite in the steering wheel of all cars. Have a detector that will detonate it in any crash. Let people know that this is the case. Let people know that they should drive very carefully.
You may think this is absurd, but look at the benefits:
People will have a very strong motivation to drive carefully
There will be evolutional pressure for the human race to become more carefull (or at least better drivers)
It would help keep population growth under control
A population that dies younger will help relieve some of the stresses on Social Security, Medicare, etc.
All that scrap metal could be recycled
Emergency crews wouldn't be so hard-pressed to get to the scene of an accident quickly. I mean, everyone's already dead, so take your time.
Oh yes, I absolutely definitely use and love Putty. It's one of the ones that I left unsaid because several other people had mentioned it.
However, when I open up Putty and try to connect to COM1, it becomes less optimal of a solution. For that, TerraTerm isn't perfect, but sure beats the crap out of HyperTerminal.
I know serial support in putty is somewhere on the wish list, but if you know of a really nice serial console for windows, I'd love to know about it. Actually, I'm not thrilled with Minicom either, so if you know a good one for Linux, that'd be cool too.
The kind of stuff we have to deal with from nuclear power plants is nasty. WAY nastier than anything which comes out of a traditional power plant.
Sometimes. Sometimes not. On my college campus there was a small (6 MW IIRC) nuclear reactor, used for instruction in the Nuclear Engineering courses. I took a tour of it once (I was in Chem E, not Nuc. E, so I never got to do any actual work with it) and heard an interesting story from one of the professors there.
They were doing a scheduled test one weekend of some of the safety systems, so they were expecting some alarms going off. One of the students walked in the door, and suddenly all of the radiation alarms went off. They got out their gear and traced it down to the student who had just walked in. Specifically, they tracked it down to his head. So they got a 55 gallon drum of water and started washing his head. After a little bit of that, the water was radioactive, but his head wasn't. After they were finished, he told them what he had done. He had gone to WalMart and bought a wick for a coleman propane lantern. He took some scisors and cut it up into fine pieces, and sprinkled it on his head (The wicks are coated with a chemical which gives it a cleaner, whiter light, and also happens to be slightly radioactive).
The amusing thing about all of this is the contrast between normal use and a nuclear power plant. 99.99999% of the coleman wicks that are sold are thrown away in the trash (or littered with near campsites) because they really are not a hazard to anyone, and no sane person would say they are. However, because he brought the one he bought into a nuclear power plant, the plant had to classify the whole 55 gallons of water as potentially dangerous nuclear waste, and they had to spend a fairly large amount of money to have it disposed of "properly". How much of the nuclear waste that's being encased in concrete and buried under miles of rock is more (or less) dangerous than what you can buy in the local WalMart?
One thing that strikes me as odd about this idea, my understanding of the general profile of kidnapping in the US is that many, or possibly a majority, of kidnappings are done by the current or former spouse of a parent who isn't happy with current or predicted custody arangements. Having a GPS on a child might make it easier for kidnappers with specific targets (such as the aforementioned disgruntled ex-spouse, or someone who thinks that you are a good target for extracting ransom) to find their victims, and more importantly to track them to a place where they will be easier to nab.
Well, a turkey can be cooked much more rapidly if you put it in a microwave. Most people don't, because they'd rather get the nice look and taste of a turkey that has had its outer skin "baked" by the application of intense IR radiation. My understanding of the plan referenced in the article was to beam down, not concentrated solar radiation, but microwaves powered by concentrated solar radiation. IR, UV, and visible light are all absorbed within the first few millimeters of skin and flesh that they hit. A quick google turns up this page, which discusses the amount of signal loss of microwaves passing through a human body. This indicates to me that, not only do microwaves have a good chance of fairly evenly distributing their power throughout a human body, but that much of the energy will pass straight through a human body (my understanding of microwave ovens is that their internal surfaces are reflective to microwaves, so that the radiation being emitted by the magnetron is bounced back and forth through the target until signal attenuation reaches 100%)
So, my understanding is that you would be completely right if the beam were composed of IR, visible light, UV, or many other wavelengths (or a combination of a large range, much like solar radiation is), however the microwave radiation that this beam is meant to be composed of is much more penetrating than that, and would more accurately approximate my set of assumptions.
Erm, which way would that be? The way I see it, the fastest way to figure out that the beam is off-target is at the ground site. Once the ground site knows the beam is off-target, it sends a signal to the transmitter to shut it off. That signal goes at the speed of light, taking one second. As soon as that signal hits the transmitter, the transmitter shuts off, but there is already one second's worth of beam in transit. Total time from detecting the beam being off-target to the beam no longer impacting the ground is one round-trip time, or about two seconds. Don't see how that could be improved upon. Of course, this is all worst-case. If the transmitter can tell that it's off-target without information from the ground, then they can actually shut it off before the ground knows they've gone off-target (but the beam that's still in transit will still hit, one second later)
OK, here's my quick off-the-cuff calculations on this:
assumptions:
the beam is 3.6Gw (which is a fairly large amount...) collector is 100 M on a side (10,000 sq m) nearest un-shielded habitation is 2km away out-of-alignment condition will be noticed immediately, but will take one speed-of-light rtt to shut down (note, if the collector is on the lunar surface, but relay satellites are in geosync, then the rtt from the geosync satellites is about.6 seconds, as opposed to the approx 2 seconds rtt to luna) worst-case scenario is a prostrate person occluding 1 sq. M of space.
calculations:
The beam is delivering 360 Kw/sq m, 100 watt-hrs/sq meter/second. Worst-case, the beam travels the 2km in exactly the 2 seconds of rtt. The hundred meters of beam width will pass over any point along that path in approx.1 seconds, adding 10 watt-hr/sq meter, i.e., 10 watt-hr to our worst-case prostrate person. If I'm doing my calculations correctly, that's about 9000 calories. I occlude about 1 square meter, and mass about 100 kilos. One calorie raises one gram one degree celcius, so that energy would raise my body temperature by.09 degrees celsius, which I doubt I would notice.
Now, the *really* worst case scenario would be if the beam traveled the 2Km in.000001 seconds, and then stopped dead for 2 seconds. That would deliver 200 watt-hrs, elevating the temperature of prostrate people in the vicinity by about 1.8 degrees celsius, which would probably be noticable, but unlikely to be deadly (and extremely unlikely to melt the ground to a puddle of glowing magma...) (of course, all of this assumes that the person is absorbing 100% of the transmitted energy.) However, it seems to me that there are reasonably simple ways to make this sort of failure much more difficult (I'm thinking that the relay station is in two components, a transmitter and a colimator, tethered together with the center-of-gravity of the entire structure being in geosync and tidal forces providing tension on the tethers. Put a wave-guide assembly between the transmitter and the colimator so that mis-alignment will turn it from a wave guide into a reflector. That would mean that a drift off-target would require the entire assembly to move, so you've got a lot of inertia guaranteeing that drift will tend to be constant, as opposed to jerking far off target and then stopping suddenly)
Well, the thing that bugs me about this solution is that it seems really easy to get around.
Right now verisign has the equivalent of, in the.com zone:
* IN A 64.94.110.11
Now, it seems to me that it would be really simple for them to change that to something more like:
* IN NS ns.searchstation.com
(and, of course, a wildcard A record in ns.searchstation.com) To me, it looks like the only way to get around this more permanently is to have BIND check periodically for some known-not-to-exist domain name (figuring that one out might be tricky), and use the reply as a reference. If it gets other replies like that, then return NXDOMAIN.
I do find it kind of interesting that, at this time, verisign is only returning wildcard A records, not NS, not MX, not SOA. Hmmm.
First of all, note that it's only members.aol.com that seems to be doing this.:
telnet www.aol.com 80 GET / HTTP/1.1 Referer: http://www.livejournal.com/ Host: www.aol.com
HTTP/1.0 200 OK Server: AOLserver/3.4.2 ...
telnet members.aol.com 80 GET / HTTP/1.1 Referer: http://www.livejournal.com/ Host: members.aol.com
HTTP/1.1 404 Not Found Server: Apache/1.3.26 (Unix) Resin/2.0.5 Vary: Referer Cache-Control: private Content-Length: 7680 ....
More importantly, if not crucially, it seems to be specifically blocking referer headers of exactly "http://www.livejournal.com/*" "http://livejournal.com/" isn't blocked, and neither is "http://aol.livejournal.com/". It seems to me that a single virtualhost with a redirect directive, an additional dns entry, and a big honkin' sed script would fix the problem. Until aol blocks *.livejournal.com. At which point the redirector should be moved to a new domain, until aol has no choice but to block *.com, *.net, *.edu, and *.??. Then the only people able to look at aol will be those referred to it from.mil and.gov sites. Fitting punishment.
Slashdot Mirror
Actually, for the types of applications they're talking about, I think I'd prefer a hydraulic elevator. I'm guessing that there must be some sort of advantage to this vacuum system or else there'd be no market for it (although, there's little evidence that there actually is a market for it). Maybe there is some value to this system. Perhaps it's cheaper. Perhaps it's better in some way that I haven't yet discerned. Or, perhaps the investors in this company are just idiots. Whatever. I don't personally see the allure. And I 100% agree with the statements about being able to store overpressure in a tank. You can store vacuum in a tank, but the highest pressure differential you can possibly get is 15psi. So you'd need a really significantly larger tank to store the vacuum in.
It would seem to me that there's a limit to the amount of vacuum you can get above an elevator, but no limit in the pressure you could generate below it. I mean, if the elevator is 4 feet across, then the absolute theoretical limit of wieght that could be pulled up by suction (assuming standard sea-level pressure) would be...
interesting. Google can't parse:
(pi * ((inches in 1 foot * 2)^2) * psi in 1 atm) / lbs in 1 ton
but substituting in values, you get:
(pi * ((12 * 2)^2) * 14.6959488) / 2000 = 13.2965812
OK. I guess that's not so very strange after all. In a 4 foot wide elevator, you can lift 13 tons with a hard vacuum above it. Damn. 15psi sure does add up quick.
If, theoretically, I personally were to get infected with some sort of phishing keystroke logger, what would an attacker get? well, besides this post, they would get... some oddness. I click on my mozilla icon, I click on my bookmark for my online banking, I click on the link to passwordsafe, I enter the password for my local password database (which, of course, is an extremely sensitive password, but isn't of much use to someone who doesn't have the database file itself.) I double-click the entry for my online banking info, and hit "ctrl-v".
Of course, if an attacker could install a keystroke logger, he could also steal my passwordsafe database. Or he could copy off the contents of my clipboard at the appropriate time. Or he could corrupt my browser and pervert it such that, for instance, it would send the data in any https-based POST's to him as well. But all of those further fragment his attack strategy. What about people who use password managers other than passwordsafe? How about people who use different browsers? Will he write his software to pervert IE, Mozilla, Firefox, Opera, lynx? It does make his challenge a bit tougher... Which is always a good thing.
The two main reasons would be:
If someone is considering pirating proprietary software, I will suggest they try an open-source alternative first because, well, I actually *do* care about software piracy.
Second, I will suggest things like firefox and thunderbird to people, because if my suggestion means that one random user *might* install said software, that user will have a *slightly* better chance of not becoming part of some evil hacker's vast zombie network, and that makes *my* network more secure. It's a very slight gain, which is why I don't put a lot of effort into it, but a successful suggestion to a random user *will* perk up my day for this reason. Kinda like finding a penny on the street.
Cool. They were dumpster diving for antiquities. Sweet.
Anyone else read the title and think that maybe the DEA had busted NASA? And that this could just be one of the cleverest smuggling ideas yet?
"Yes, Binky, we'll smuggle our crack ballistically!"
Or is that just me?
I would submit that
Absolutely. Replace your force-feedback mouse with the new force-bitchslap mouse.
WHAP! No clicky!
That said, there are some usefull things you could do with this. One example I can think of would be to detect some obfuscated scanning techniques. As an example, nmap impliments idle scanning, which is usually reasonably obvious because of the characteristic SYN->SYN/ACK->RST sequence, especially if the SYN and RST have different TTL's. Adding timestamp checks would make it more obvious (although, just as difficult to track down the original scanner).
Also, if someone used a decoy scan in nmap, it might be reasonably easy to tell which source addresses were really the same machine. You would probably also get enough information to construct a fairly accurate timestamp/skew profile of that machine. If you ever saw those IP addresses again, then you'd be able to check whether it was the real machine.
But, these are just my own ramblings. At the very least it seems to be interesting work (although the article linked is pretty crummy)
Pointless for anti-theft, but looks like it could be usefull for social engineering. Showing up at someone's office building with a laptop and saying "hey, can I plug into your internal network for a few minutes?" isn't likely to have too much success. Your chances are much better if you show up with 1) a tool belt and CWA polo shirt, 2) a pizza box, or 3) a cleaning cart and a complete inability to speak english.
Of course, the real hilarity ensues when you bring your pizza box with a laptop in it with you to the airport...
But it's such an idiotic statement to begin with. Of course tabbed browsing isn't important to IE users. If it were important to someone, they would cease to be an IE user. It would be a similar statement to say that "Features such as high gas mileage are not important to Hummer users." While the statement is true, it has no bearing on whether or not high gas mileage is important to users of cars. Similarly, tabbed brwosing is important to many browser users, but not all. Probably, most of the browser users out there for whom it is important are using Firefox, Mozilla, Opera, etc., while some of the users for whom it is not important may be using IE (unless there is some other feature that IE lacks and other browsers have).
"Virginia is considering just such a measure, largely because several of the 9/11 hijackers were licensed there."
because wouldn't everyone agree that it would have been just so much better if the 9/11 hijackers had Virginia drivers licenses with RFID chips embedded in them when they flew into the WTC. Sigh. Putting RFID chips in drivers licenses doesn't make it any harder for someone (terrorist or not) to get a drivers license. It wouild make just about as much sense to say "Virginia is considering just such a measure because tasty smoked ham is made in Virginia. There's no correlation between the two, but every effect must have a cause, so we'll use ham." I'm thinking that the "logic" here is that if they know someone is a terrorist, they can use RFID chip scanners to find them more easily. But if you know someone's a terrorist, then maybe you should arrest them when they come to pick up their driver's license in the first place, or when they get their airline ticket, or when they get pulled over by a cop for speeding, or at any other time when they actually present their driver's license and/or name. This is a solution to a problem we'd love to have. If someone could solve the problem of figuring out who's a terrorist, and the only obstacle was in finding them, then maybe this would be usefull. As it is, this is a solution to a problem that doesn't exist.
There is the "worst movie that I was looking forward to", i.e. one that I thought I might enjoy, but was horribly, horribly disappointed at. That would have to be Highlander 2.
And then there's just plain bad. I'm thinking that would be The Cars that Ate Paris. (and no, it's not a porno about a 70's Boston rock band's sexual escapades with a vapid blonde heiress. That might have at least been funny.)
Well, you can't make an omlette without breaking some eggs is what I say. :)
What would cthulhu do indeed.
You may think this is absurd, but look at the benefits:
Oh yes, I absolutely definitely use and love Putty. It's one of the ones that I left unsaid because several other people had mentioned it.
However, when I open up Putty and try to connect to COM1, it becomes less optimal of a solution. For that, TerraTerm isn't perfect, but sure beats the crap out of HyperTerminal.
I know serial support in putty is somewhere on the wish list, but if you know of a really nice serial console for windows, I'd love to know about it. Actually, I'm not thrilled with Minicom either, so if you know a good one for Linux, that'd be cool too.
Many things already mentioned, and then add Ethereal, PasswordSafe, TerraTerm, Vim.
(at least, for windows boxes)
Sometimes. Sometimes not. On my college campus there was a small (6 MW IIRC) nuclear reactor, used for instruction in the Nuclear Engineering courses. I took a tour of it once (I was in Chem E, not Nuc. E, so I never got to do any actual work with it) and heard an interesting story from one of the professors there.
They were doing a scheduled test one weekend of some of the safety systems, so they were expecting some alarms going off. One of the students walked in the door, and suddenly all of the radiation alarms went off. They got out their gear and traced it down to the student who had just walked in. Specifically, they tracked it down to his head. So they got a 55 gallon drum of water and started washing his head. After a little bit of that, the water was radioactive, but his head wasn't. After they were finished, he told them what he had done. He had gone to WalMart and bought a wick for a coleman propane lantern. He took some scisors and cut it up into fine pieces, and sprinkled it on his head (The wicks are coated with a chemical which gives it a cleaner, whiter light, and also happens to be slightly radioactive).
The amusing thing about all of this is the contrast between normal use and a nuclear power plant. 99.99999% of the coleman wicks that are sold are thrown away in the trash (or littered with near campsites) because they really are not a hazard to anyone, and no sane person would say they are. However, because he brought the one he bought into a nuclear power plant, the plant had to classify the whole 55 gallons of water as potentially dangerous nuclear waste, and they had to spend a fairly large amount of money to have it disposed of "properly". How much of the nuclear waste that's being encased in concrete and buried under miles of rock is more (or less) dangerous than what you can buy in the local WalMart?
One thing that strikes me as odd about this idea, my understanding of the general profile of kidnapping in the US is that many, or possibly a majority, of kidnappings are done by the current or former spouse of a parent who isn't happy with current or predicted custody arangements. Having a GPS on a child might make it easier for kidnappers with specific targets (such as the aforementioned disgruntled ex-spouse, or someone who thinks that you are a good target for extracting ransom) to find their victims, and more importantly to track them to a place where they will be easier to nab.
Well, a turkey can be cooked much more rapidly if you put it in a microwave. Most people don't, because they'd rather get the nice look and taste of a turkey that has had its outer skin "baked" by the application of intense IR radiation. My understanding of the plan referenced in the article was to beam down, not concentrated solar radiation, but microwaves powered by concentrated solar radiation. IR, UV, and visible light are all absorbed within the first few millimeters of skin and flesh that they hit. A quick google turns up this page, which discusses the amount of signal loss of microwaves passing through a human body. This indicates to me that, not only do microwaves have a good chance of fairly evenly distributing their power throughout a human body, but that much of the energy will pass straight through a human body (my understanding of microwave ovens is that their internal surfaces are reflective to microwaves, so that the radiation being emitted by the magnetron is bounced back and forth through the target until signal attenuation reaches 100%)
So, my understanding is that you would be completely right if the beam were composed of IR, visible light, UV, or many other wavelengths (or a combination of a large range, much like solar radiation is), however the microwave radiation that this beam is meant to be composed of is much more penetrating than that, and would more accurately approximate my set of assumptions.
Erm, which way would that be? The way I see it, the fastest way to figure out that the beam is off-target is at the ground site. Once the ground site knows the beam is off-target, it sends a signal to the transmitter to shut it off. That signal goes at the speed of light, taking one second. As soon as that signal hits the transmitter, the transmitter shuts off, but there is already one second's worth of beam in transit. Total time from detecting the beam being off-target to the beam no longer impacting the ground is one round-trip time, or about two seconds. Don't see how that could be improved upon. Of course, this is all worst-case. If the transmitter can tell that it's off-target without information from the ground, then they can actually shut it off before the ground knows they've gone off-target (but the beam that's still in transit will still hit, one second later)
OK, here's my quick off-the-cuff calculations on this:
.6 seconds, as opposed to the approx 2 seconds rtt to luna)
/second. Worst-case, the beam travels the 2km in exactly the 2 seconds of rtt. The hundred meters of beam width will pass over any point along that path in approx .1 seconds, adding 10 watt-hr/sq meter, i.e., 10 watt-hr to our worst-case prostrate person. If I'm doing my calculations correctly, that's about 9000 calories. I occlude about 1 square meter, and mass about 100 kilos. One calorie raises one gram one degree celcius, so that energy would raise my body temperature by .09 degrees celsius, which I doubt I would notice.
.000001 seconds, and then stopped dead for 2 seconds. That would deliver 200 watt-hrs, elevating the temperature of prostrate people in the vicinity by about 1.8 degrees celsius, which would probably be noticable, but unlikely to be deadly (and extremely unlikely to melt the ground to a puddle of glowing magma...) (of course, all of this assumes that the person is absorbing 100% of the transmitted energy.) However, it seems to me that there are reasonably simple ways to make this sort of failure much more difficult (I'm thinking that the relay station is in two components, a transmitter and a colimator, tethered together with the center-of-gravity of the entire structure being in geosync and tidal forces providing tension on the tethers. Put a wave-guide assembly between the transmitter and the colimator so that mis-alignment will turn it from a wave guide into a reflector. That would mean that a drift off-target would require the entire assembly to move, so you've got a lot of inertia guaranteeing that drift will tend to be constant, as opposed to jerking far off target and then stopping suddenly)
assumptions:
the beam is 3.6Gw (which is a fairly large amount...)
collector is 100 M on a side (10,000 sq m)
nearest un-shielded habitation is 2km away
out-of-alignment condition will be noticed immediately, but will take one speed-of-light rtt to shut down (note, if the collector is on the lunar surface, but relay satellites are in geosync, then the rtt from the geosync satellites is about
worst-case scenario is a prostrate person occluding 1 sq. M of space.
calculations:
The beam is delivering 360 Kw/sq m, 100 watt-hrs/sq meter
Now, the *really* worst case scenario would be if the beam traveled the 2Km in
Right now verisign has the equivalent of, in the
To me, it looks like the only way to get around this more permanently is to have BIND check periodically for some known-not-to-exist domain name (figuring that one out might be tricky), and use the reply as a reference. If it gets other replies like that, then return NXDOMAIN.
I do find it kind of interesting that, at this time, verisign is only returning wildcard A records, not NS, not MX, not SOA. Hmmm.
So now we know the answer to the burning question: How many companies does it take to replace a lightbulb.
Three. One to use LED's, one to ???, and one to profit.